Several approaches to interactive video have been developed to allow a user to interface with digital video systems. One such approach provides optional side trips, which allow users to follow a link out of the currently playing video in order to watch an alternate video sequence. At the end of the alternate sequence, or upon user input, the video presentation returns to the original video departure point and continues to play from that point. For example, some DVDs include options for viewers to follow links out of the currently playing video to watch other video clips. When a link is active, an icon appears on top of the playing video. The viewer can press a button on a remote control to jump to the alternative video. For example, certain DVD movies provide links that take a viewer to video segments explaining how a particular scene in the movie was filmed. Afterwards, the original video continues from where the viewer left.
Expanding on the concept of optional side trips in video, detail-on-demand video includes one or more base video sequences each having one or more alternate video sequences. Each alternate video sequence provides additional details related to the base video sequence. During video playback, users can select the alternate video sequence to view this additional detail.
Upon user input or completion of the alternate video sequence, the presentation returns to the base video sequence. The author may determine the location where the presentation resumes. Additionally, alternate video sequences can include links to other video sequences, thereby creating a hierarchical structure in which video sequences providing additional detail may in turn contain links for sequences having even more detail.
The nature of detail-on-demand video is well suited for applications such as creating training or “how-to” videos. In such an application, viewers can control the level of explanation they receive by following links to the appropriate level. Base video sequences can present an overview of the information at an abstract or relatively “high” level. Users can follow a link from a base video sequence in order to view a more detailed presentation in an alternate video sequence. Further detail can be provided by linking the alternate video sequence to yet another video sequence, which in turn can link to another video sequence, and so on. This hierarchical presentation allows the viewer to select and view detailed presentations of certain topics, such as topics in which the viewer needs the most help, while skipping over or viewing high-level presentations of more familiar portions. Such video guides can serve a wide audience by presenting a customized level of detail for each viewer, and can save the viewer time by avoiding detailed presentations of information already familiar to, or of little interest to, the user.
Home video editing is another application for detail-on-demand video. Home users can create video summaries of family activities or other home movies. More detailed presentations of different activities can be linked to the base video sequence to provide additional footage of interest. For example, a family video Christmas card may contain a main video sequence summarizing family activities for the year. Viewers can select a link during each portion of the main video sequence to view additional video from the family activity of interest. For example, a grandparent may select additional video sequences of grandchildren, while other relatives may select addition details of a party or family reunion.
Detail-on-demand video was designed to support the authoring and use of interactive video in a wide variety of applications. Characteristics of video representations meeting this design goal include a hierarchical structure where video clips are combined into composites, as well as links between elements in this hierarchy.
FIG. 1 shows a diagram of an exemplary detail-on-demand summary as described in U.S. patent application Ser. No. 10/116,026, including two hierarchically organized video segments 100, 110 and three links 116, 118, 120 between those video segments. The first link 116 is from “composite 3” 104 to “composite 6” 110, the second link 118 from “clip 5” 122 to “composite 8” 114 and the third link 120 from “clip 11” 126 to “clip 7” 124. If more than one link can be active at a particular time, which can happen if links are specified for multiple levels of the hierarchy, the lowest-level link can be set to have precedence.
While detail-on-demand videos can provide an interactive summary for access into longer linear videos, human authoring of such summaries is very time consuming and not cost effective if the summary will only be used a few times. While the editing of video typically involves the selection and sequencing of video clips into a linear presentation, which in itself can be a lengthy process, authoring detail-on-demand video is more complicated as it involves the authoring and interlinking of one or more such linear video presentations.
In many such presentations, individual video clips must be selected and grouped into video composites as higher-level building blocks. Video clips and/or composites must be selected to be the source or destination anchor for each navigational link used to link the building blocks of related material. Source anchors must be selected that can specify the starting point at which a link becomes active, as well as the length of time for which the link is active. Destination anchors must be selected that can specify the starting point and length of the video played as a result of a viewer traversing the active link. Unlike hyperlinks in Web pages or in most hypervideo systems, the link destination is not just a starting point but an interval of content. The person creating the summary must also determine where playback will continue upon completion of the video viewed using the link or when the viewer aborts the playing of that video.
The length of time necessary for an individual to create such a detail-on-demand summary can be undesirable in many situations, such as the summarizing of home movies for consumer applications. It would be preferable in many situations to present a way to shift most, if not all, of the time and effort necessary to create such hypervideo summaries away from the end users.